REPAIRING AND NOT THROWING AWAY

REPAIRING AND NOT THROWING AWAY

Richtige Fernseher haben Röhren!

Richtige Fernseher haben Röhren!

In Brief: On this site you will find pictures and technical information about Service Modes, Circuit Diagrams, Firmware Update procedure, Disassemble procedure, Universal remote control set-up codes, Troubleshooting and more....

If you go into the profession, you will obtain or have access to a variety of tech tips databases HERE IT IS Master Electronics Repair !.

These are an excellent investment where the saying: 'time-is-money' rules. However, to learn, you need to develop a general troubleshooting approach - a logical, methodical, method of narrowing down the problem. A tech tip database might suggest: 'Replace C536' for a particular symptom. This is good advice for a specific problem on one model. However, what you really want to understand is why C536 was the cause and how to pinpoint the culprit in general even if you don't have a service manual or schematic and your tech tip database doesn't have an entry for your sick TV or VCR.

While schematics are nice, you won't always have them or be able to justify the purchase for a one-of repair. Therefore, in many cases, some reverse engineering will be necessary. The time will be well spent since even if you don't see another instance of the same model in your entire lifetime, you will have learned something in the process that can be applied to other equipment problems.
As always, when you get stuck, checking out a tech-tips database may quickly identify your problem and solution.In that case, you can greatly simplify your troubleshooting or at least confirm a diagnosis before ordering parts.

Happy repairing!
Today, the West is headed for the abyss. For the ultimate fate of our disposable society is for that society itself to be disposed of. And this will happen sooner, rather than later.

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..............The bitterness of poor quality is remembered long after the sweetness of todays funny gadgets low price has faded from memory........ . . . . . .....
Don't forget the past, the end of the world is upon us! Pretty soon it will all turn to dust!

©2010, 2011, 2012, 2013, 2014 Frank Sharp - You do not have permission to copy photos and words from this blog, and any content may be never used it for auctions or commercial purposes, however feel free to post anything you see here with a courtesy link back, btw a link to the original post here , is mandatory.
All posts are presented here for informative, historical and educative purposes as applicable within fair use. NOTHING HERE IS FOR SALE !

Thursday 21 March 2019

AKIRA 14KLS4-CE TV - [LA-76931 IC] - SERVICE DETAILS - FACTORY MENU - POWER SUPPLY SMPS - SCHEMATIC

AKIRA 14KLS4-CE TV - [LA-76931 IC] - SERVICE DETAILS - FACTORY MENU - POWER SUPPLY SMPS - SCHEMATIC


  • POWER SUPPLY CHECK
Check input voltage  → check voltage of C910 anode → check Pin 3 of N901 → check V901 → check output voltage of T901 secondary coil  → check voltage of N904, N905 Pin 3 (5.0v) and N903 Pin3 (9.0V) → check voltage of N103 Pin 8, 31, 32, 35, 36, 43, 55 (5v) and Pin 11, 19 (8v) → check voltage of N602 Pin 8 (+5V).
  • AUDIO CIRCUIT
Check power supply of audio power amplify circuit →check input audio signal of audio power amplifier circuit → check waveform of N103 Pin 5→ check waveform of xs808 Pin 16, 17→ check waveform of N201 Pin 8, 10.
  • HORIZONTAL CIRCUIT
Check voltage of T402 Pin 3 (110V)→ check voltage of N103 Pin 19 (+9.0V) → check waveform of V401 Base → check waveform of V402 Collector → check output voltage of T402 coil →check waveform of T402 Pin 8.
  • VERTICAL CIRCUIT
Check voltage of N440 Pin 2 (+25V) and Pin7 (+9V) → check voltage of N103 pin 19 (+9V) → check waveform of N103 Pin 17 → check waveform of N440 Pin 1  → check waveform of N440 Pin 5.
  • MCU CIRCUIT
Check voltage of N103 Pin 31, 32 (5v) →  check waveform of N103 Pin 33
  • FACTORY MENU

Press MENU button on the remote control firstly, then the press RECALL button three times sequentially to enter ‘FACTORY MENU.’
Press P+ or P- button on the remote control to select test item.
Press V+ or V- button on the remote control to adjust the value of selected item.
Press RECALL button again to exit FACTORY MENU.
  • Power Supply and Voltage adjustment
a. Check AC voltage is normal or not, AC220V 50Hz.
b. Receive Television broadcast signal adjust Brightness and Contrast until the standard picture is obtained.
c. Adjust RP950 until voltage between cathode of VD950 and GND of chassis is 110V±0.5V.
  • High Voltage check
a. Use 220V power supply to measure that power supply is up to standard before checking the high voltage.
b. Connect the precise high voltage meter to second anode of CRT.
c. Turn on the receiver, adjust Brightness and Contrast until the standard picture is obtained and set the screen “OFF”.
d. Switch the receiver to AV, High voltage must be measured below 25kv.
  •  Geometric Distortion and Sub-brightness adjustment
a. Receive black-white PAL five circles pattern signal, and set the picture to standard mode, apply 80dBμV signal.
b. Enter into factory sub-menu FACTORY MENU 00 to adjust the following items.
c. Use P+/P- button to choose the adjustable item.
d. Use V+/V- button to adjust the parameter.
  • White balance and sub-brightness adjustment
Note: BLUE BACK must be turned off and factory menu must be ON before placing the set with aging test.
a. Set Unit to AV, use oscilloscope to check CRT board B out. Then adjust brightness to make the B out cut off point is 160V±2V.
b. Disconnect the oscilloscope, enter FACTORY MENU 00, press P+ or P- button to choose V-KILL, then press V+ button to display horizontal light line on the screen, adjust SCREEN potentiometer so that the horizontal light line just displays anyone color of R, G and B, press V- button to restore the screen.
c. Input left black and right white signal for white balance adjustment.
d. Insert I2C controller plug, which is used for automatic adjustment system into XS600 socket on the main board.
e. Turn on color analyzer CA100 to make zero correction.
f. Run the program [WB76810.exe t213.wbd]
g. Press “SPACE” key or press switch on the controller socket, white balance adjustment will be operated automatically. If OK, “ Click” will be heard.
h. Pull out I2C controller plug from XS600, receive black-white PAL five circles pattern signal, and set the picture to standard mode.
Enter FACTORY MENU 00, adjust sub-brightness until black-white gray scale is 6.5~7.
  • HF AGC automatic adjustment
a. Receive signal (VHF channel)
b. Set input field strength to 60dBμV
c. Enter into FACTORY MENU 00, select RF AGC item, press V+ button to adjust RF AGC automatically, and when the adjustment is finished the screen will display RF AGC value.
  • OSD position adjustment
a. Receive PAL five circles pattern signal.
b. Enter into FACTORY MENU 00 and select OSD-H-POSITION, then press V+/V- button to adjust OSD to the proper position.

SMPS POWER SUPPLY [Click on image to Enlarge]
Posted By: FRANK at 02:17
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